Britain's Borders Agency is today accused of trying to “circumvent” attempts by Parliament to get the information MPs need to hold the organisation to account.

In its third damning report into the UKBA in just a year the Home Affairs Select Committee said the agency was unacceptably “obstructive” when asked to provide essential information.

It added that its “bunker mentality” risked raising suspicions that it was trying to mislead Parliament and the public.

In a wide ranging and critical report the committee said the agency was still failing to fulfill its basic tasks and risked damaging public trust in the Government.

It said figures supplied to the committee showed a fifth of foreign prisoners, some 1,060 criminals, who finished their jail terms in 2010/11 had still not been deported by November last year.

Almost 20,000 asylum cases also remain unresolved and some 120,000 immigration cases were written off because the applicant can no longer be found, it added.

Keith Vaz, the committee's chairman, said: “The reputation of the Home Office, and by extension, the UK Government, is being tarnished by the inability of the UK Border Agency (UKBA) to fulfil its basic functions.

“The foreign national prisoner issue and the asylum backlog were scandals which first broke in 2006, six years ago.

"UKBA appears unable to focus on its key task of tracking and removing illegal immigrants, overstayers or bogus students from the country.”